1. Field of the Invention
The present invention relates to a cigarette and, more specifically, to an improvement in plug wrap paper used for a cigarette capable of reducing a variation in the amount of air flow from a filter (filter ventilation).
2. Description of the Related Art
A conventional cigarette filter is cylindrically formed of a fiber filter material such as cellulose diacetate wrapped by a plug wrap paper. A tipping paper is used to connect a filter rod and a tobacco rod. Vented filters each made by the combination of an air-permeable plug wrap paper and a tipping paper having pores formed by means of static electricity, a laser beam, etc. have recently been used widely to allow air to enter through the periphery of the filter and reduce the yield of smoke effusing through the filter rod. With the vented filter having the above-described structure, dilution air is inhaled into the smoker's mouth from the outer portion of the mouth end face of the filter, whereas tobacco smoke is inhaled into the mouth from the center portion of the mouth end face.
It has been confirmed that the conventional cigarette described above entails the problem of a large variation in filter ventilation even though the filter fiber, plug wrap paper, and tipping paper of the cigarette are made of the same material. Since the filter ventilation is greatly correlated with the amount of smoke inhaled, the variation in the filter ventilation is undesirable.